54 



GENERAL REMARKS ON INSECTS. 



from the ameliorating influence of the river, be said to be a month longer 

 —a fortnight earlier in spring and later in autumn — than in the same 

 latitude a few miles distant ; and cro})S of the more tender fruits are 

 therefore much more certain on the banks of large rivers or lakes than in 

 inland districts of the same climate. 



As our native forests become cleared away the climate is changed 

 and becomes more harsh ; hence it is found desirable to construct some 

 kind of protection from the point of most destructive harsh winds and 

 storms. Belts of trees, either evergreen oi' deciduous, or both mingled, 

 and surrounding or placed so as to screen from the northeast, north, and 

 northwest, are considered highly advantageous ; and when we consider 

 that foliage is an absorbent and ameliorating agent in tempering climate, 

 we feel that it is the duty as well as interest of every fruit-grower to 

 plant as many such belts as his property and pecuniary means admit. 



CHAPTER YIII. 



GENERAL REMARKS ON INSECTS. 



The insects injurious to fruit-trees are numerous, and to combat them 

 successfully requires a minute acquaintance with their character and 

 habits. While considering the culture of each class of fruit in the suc- 

 ceeding pages, we shall point out the habits and suggest means of de- 

 stroying the most important of these insects ; but in the mean time 

 we wish to call attention to some general practical hints on this sub- 

 ject. 



In the first place, we cannot too strongly impress upon the attention 

 of the fruit-grower the importance of watching carefully and making an 

 early attack upon every species of insect. It is only necessary to look 

 for a moment at the astonishing rapidity with which many kinds of 

 insects increase, if allowed to get well established in a garden, to become 

 fully aware of this. The common caterpillars are the young of moths or 

 butterflies, and that careful observer of the habits of insects. Dr. Harris, 

 says as each female lays from two to five hundred eggs, a thousand moths 

 or butterflies will, on the average, produce three hundred thousand cater- 

 pillars ; if one half this number, when arrived at maturity, are females, 

 they will give forty-five millions of caterpillars in the second, and six 

 thousand seven hundred and fifty millions in the third generation.* To 

 take another example : the aphides^ or plant-lice, which are frequently 

 seen in great numbers on the tender shoots of fruit-trees, have an almost 

 incredibly prolific power of increase — the investigations of Reaumur 

 having shown that one individual in five generations may become the 

 progenitor of nearly six thousand millions of descendants. With such 

 surprising powers of propagation, were it not for the havoc caused 

 among insects by various species preying upon each other, by birds and 

 other animals, and especially by unfavorable seasons, vegetation would 



* For much valuable information on the habits of insects injurious to vegeta- 

 tion, see the " Treatise on the Insects of Massachusetts," by Dr. T. W. Harris, 

 Cambridge. 



